posted by Jenn .
Compounds like CCL2F2 are known as chloroflourocarbons, or CFCs. These compounds were once widely used as refrigerants but are now being replaced by compounds that are believed to be less harmful to the environment. The heat of vaporization of CCl2F2 is 289J/g. What mass of this substance must evaporate in order to freeze 100g of water initially at 18 C. (The heat of fusion of water is 334J/g; the specific heat of water is 4.18J/g-K).
How much heat must be lost to move H2O from 18 to 0 degrees C?
mass x specific heat x delta T =
100g x 4.186 J/g*C x 18 = ??
How much heat must bae lost to freeze the water?
100g x 334 J/g = ??
Total heat that must be lost (pulled out of the water) is the sum of the two.
How much heat can the CCl2F2 remove?
mass x 289 J/g = ??
Can you take it from here?